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Nonlinear bending of functionally graded metal/graphene (FGMG) sandwich rectangular plate with metal foam core resting on nonlinear elastic foundations is elucidated in this article. A new shear deformation plate theory is presented to formulate the displacement field. The nonlinear partial differential equations considering the small size effect are established via the principle of virtual work. The nonlinearity is considered by using Von Karman's strain-displacement relations. While, the size effect is captured by employing the modified couple stress theory. The upper and lower layers are made of aluminum as a matrix that reinforced with graphene platelets (GPLs). The GPLs are functionally graded through the thickness of the face layers according to a new cosine rule. Moreover, the metal foam core is also made of aluminum containing porosities that uniformly distributed or functionally graded through the core thickness. The governing equations are solved based on the Galerkin and Newton's methods. The obtained results are examined by introducing some comparison examples. In addition, several parametric examples are discussed including the effects of the porosity type, GPLs distribution type, core-to-face thickness, elastic foundation stiffness, side-to-thickness ratio, plate aspect ratio and material length scale parameter on the nonlinear deflection and stresses of FGMG sandwich plate with metal foam core. [ABSTRACT FROM AUTHOR]

In this article, we present a mathematical model of thermoelastic skin tissue based on a refined Lord–Shulman heat conduction theory. A small thickness of skin tissue is considered to be one-dimensional with mechanical clamped surfaces. In addition, the skin tissue's outer surface is subjected to ramp-type heating while its inner surface is adiabatic. A simple Lord–Shulman theory, as well as the classical coupled thermoelasticity, are also applied in this article. Laplace transform techniques and their inversions are calculated to return to the time domain. Numerical outcomes are represented graphically to discuss the significant impacts on the temperature, dilatation, displacement, and stress distributions. Such results provide a more comprehensive and better insight for understanding the behavior of skin tissue during the temperature distribution of a specific boundary condition. [ABSTRACT FROM AUTHOR]

This paper studies wave propagation in a new structure composed of three layers. The upper and lower layers are made of a piezoelectromagnetic material reinforced with graphene platelets (GPLs) that may be uniformly disseminated or continuously varied throughout the thickness of the layers. To produce a lighter plate, the core layer is assumed to comprise honeycomb structures. The smart nanocomposite plate is exposed to external electric and magnetic potentials. The effective elastic modulus of the face layers of the sandwich plate is evaluated based on Halpin-Tsai model. Whereas, the mixture rule is utilized to calculate mass density, Poisson's ratio and electric and magnetic properties of both upper and lower layers of the sandwich plate. The governing motion equations of the lightweight sandwich plate are obtained by refined higher-order shear deformation plate theory and Hamilton's principle. These equations are solved analytically to obtain wave dispersion relations. Impacts of the geometry of plates, GPLs weight fraction, GPLs distribution patterns, piezoelectric properties, external electric voltage and external magnetic potential on the wave frequency and phase velocity of the GPLs lightweight plates are discussed in detail. [ABSTRACT FROM AUTHOR]

A novel shear and normal deformations theory is presented in this article to illustrate the wave propagation and free vibration of three-layer sandwich curved beams subjected to elevated temperature and moisture environments and resting on viscoelastic foundation. The upper and lower layers are made of metal matrix reinforced with functionally graded (FG) graphene platelets (GPLs). While, the core layer is made of auxetic honeycomb structures. For the layers to be more bonded, the matrix of the face layers and the auxetic layer are both made of aluminum material. The volume fraction of GPLs is varied through the thickness of the face layers according to a layer-wise rule. The modified Halpin–Tsai model is used to describe the effective material properties of the face layers. Four types of GPLs distribution are considered in the present analysis. The differential quadrature method (DQM) is employed to discretize the equations of motion and then converted to a system of algebraic equations. This system can be solved to obtain the natural frequencies of the sandwich curved beams. Whereas, the wave dispersion relations are determined by solving the motion equations analytically. Convergence and comparison examples are presented to adjust and validate the present solution. In addition, comprehensive parametric studies are performed to investigate the effects of the weight fraction of GPLs, temperature, moisture concentrations, core thickness, boundary conditions, and viscoelastic foundation stiffness on the natural frequency, wave frequency and phase velocity of the honeycomb sandwich curved beams. [ABSTRACT FROM AUTHOR]

Abstract An analytical approach is developed to investigate the influences of hygrothermal conditions on the wave dispersion in porous graphene platelets (GPLs)-reinforced microplate embedded in the visco-Pasternak foundation. The effect of a 2D magnetic field is also considered in the present analysis. The pores and GPLs weight fraction are assumed to be non-linearly varied based on various patterns of distribution along the microplate thickness direction. Following the nonlocal strain gradient theory (NSGT) and a refined plate theory (RPT) considering the thickness stretching effect, the governing equations are obtained. The GPLs material properties are calculated employing the extended Halpin–Tsai model. The equations of motion are deduced based on Hamilton's principle. These equations are then analytically solved to obtain the wave frequency and phase velocity of the waves in a microplate. The present wave frequency and phase velocity are compared with the published ones. The impacts of GPLs weight fraction, pore coefficient, temperature rise, moisture concentration, Lorentz magnetic force, and foundation stiffnesses on the wave dispersion in the FG porous-GPLs microplate are introduced and discussed. [ABSTRACT FROM AUTHOR]

A quasi-3D refined plate theory is presented with the nonlocal strain gradient theory to investigate the wave propagation in bi-layer porous FG nanoplates surrounded by an elastic medium. Both layers are exposed to in-plane 2D-magnetic field. Maxwell's relations for perfectly conducting nanoplates are employed to derive the Lorentz magnetic force. The two porous FG nanoplates are coupled together using Winkler elastic medium. The mechanical properties of the nanoplates are continuously varied according to an exponential rule considering the porosity volume fraction. The governing equations of both layers are derived containing the plate interaction, elastic medium interaction, Lorentz magnetic force and the material length scale parameters. The frequency and phase velocity under the effects of magnetic parameter, porosity factor, elastic medium parameters, nonlocal parameter, strain gradient coefficient and nanoplate geometry are presented and discussed in detail. [ABSTRACT FROM AUTHOR]

This paper investigates the nonlinear dynamic deflection, natural frequency, and wave propagation in functionally graded (FG) porous piezoelectric microscale tubes under periodic load, hygrothermal conditions, and an external electric field. The piezoelectric material used to make the smart microtubes has pores that may be smoothly changed or uniformly distributed over the tube wall. Here, three types of porosity distribution are taken into consideration. The nonlinear motion equations are constructed using a novel shear deformation beam theory and the modified couple stress theory (MCST). The nonlinear motion equations are solved using the fourth-order Runge–Kutta technique and the Galerkin approach. The effects of various geometric parameters, porosity distribution type, porosity factor, periodic load amplitude and frequency, material length scale parameter, moisture, and temperature on the nonlinear dynamic deflection, natural frequency, and wave frequency of FG porous piezoelectric microtubes are explored through a number of parametric investigations. [ABSTRACT FROM AUTHOR]

Based on the differential quadrature method (DQM), the bending of sandwich-curved beams with graphene platelets/aluminum (GPLs/Al) nanocomposite face sheets and aluminum honeycomb core is investigated using a new shear and normal deformations curved beam theory. The present new model is resting on elastic foundation and subjected to a circumferential magnetic field, thermal load, and humid conditions. The face sheets are made of several bonded composite layers with randomly oriented and uniformly distributed graphene platelets in each layer. The mechanical and hygrothermal properties of the faces are assumed to be functionally graded (FG) using a piece-wise law by varying the weight fraction of the GPLs in the face thickness direction. Four governing differential equations are derived based on a novel four-variable curved beam theory taking into account the thickness stretching effect. The governing equations are solved for various boundary conditions on the basis of the DQM. The displacements presented by the DQM are compared with those obtained by Navier solution. Impacts of various parameters such as geometric shape parameters, magnetic parameter, temperature, moisture, elastic foundation parameters, core thickness, boundary conditions, and graphene weight fraction on the displacements and stresses of the functionally graded graphene/aluminum sandwich-curved beams are illustrated. [ABSTRACT FROM AUTHOR]

The nonlinear dynamic deformation analysis and traveling wave solution of microtubes reinforced with functionally graded (FG) graphene platelets (GPLs) embedded in Kerr foundation with three-parameter are studied. It is assumed that the composite microtubes convey a fluid and are exposed to a magnetic field. The displacement field of the microtubes is modeled using a higher-order shear deformation beam theory. Furthermore, to capture the tiny size impact, the modified couple stress theory with a single material parameter is applied. The nonlinear equations of motion of the fluid-conveying microtube are derived using Hamilton's variational principle considering von-Karman's strain–displacement relations and the fluid velocity potential. The material properties of the microtubes are calculated using the modified Halpin–Tsai model and the mixture rule. The GPL volume fraction is continuously varied across the thickness based on a refined cosine rule, taking into account different patterns of GPLs distribution. The partial differential equations are transformed into ordinary equations with different boundary conditions using the Galerkin technique. These equations are solved employing the fourth order Runge–Kutta method. While, as a special case, the nonlinear motion equation of Euler–Bernoulli microtube, that is surrounded by a shear foundation and conveying microfluid, is solved analytically based on Jacobi elliptic functions. Finally, a variety of numerical examples are presented to illustrate the impacts of magnetic field, elastic foundation parameters, material length scale parameter, flow velocity, Knudsen number, length-to-radius ratio, and length-to-thickness ratio on the nonlinear dynamic deflection and axial displacement waves in the FG-GPLs microtubes. • The nonlinear dynamic deflection of fluid-conveying FG-GPLs microtubes is illustrated. • The traveling waves along the microtube axis is discussed. • The microtubes are assumed to be surrounded by three-parameter Kerr foundations. • A one-dimensional magnetic field is applied to the fluid and the microtubes. • The small-scale effects of microtube and microfluid are taken into account. [ABSTRACT FROM AUTHOR]

Axisymmetric bending analysis of graphene platelet (GPL) sandwich annular and circular nanoplates with FG porous core and integrated with sensor and actuator resting on an elastic substrate under various boundary conditions is presented in this article. The present nanocomposite model is subjected to mechanical load and an external voltage. The upper and lower sandwich layers are made of aluminum matrix with GPL reinforcement. The effective material properties of the sandwich face layers are estimated in the framework of Halpin–Tsai scheme. In accordance with a refined four-variable theory considering the transverse shear and normal strains, the motion equations are obtained from principle of the virtual work. The size effects are considered by employing the nonlocal strain gradient theory. The differential quadrature method is utilized here to solve the governing equations. First, the obtained results are validated by implementing some comparisons with previous work. Then a comprehensive illustration is executed to show the impacts of boundary conditions, GPLs weight fraction, geometrical dimensions, elastic foundation parameters and applied voltage on the bending of the sandwich nanoplates with FG-porous core and piezoelectric layers. [ABSTRACT FROM AUTHOR]

Background and objectives: Thoracotomy is considered the most painful of surgical procedures and providing adequate analgesia is the onus for all anaesthesiologists. This study investigated the efficacy of the ultrasound-guided erector spinae plane (ESP) block in analgesia after thoracotomies. Patients and methods: Sixty patients with American Society of Anesthesiology physical status (ASA-PS) I–IV, aged more than 18 years were allocated to two groups, ESP group which received the ESP block and C (control) group with no block. Single-shot U/S-guided ESP block with 20 ml 0.25% bupivacaine at the 5th thoracic vertebral level was performed preoperatively in the ESP group. Postoperative 24 h morphine consumption and pain scores were compared between the groups. Also, the side effects of opioid usage were compared. Main results: Postoperative morphine consumption was 22.06 ± 6.24 mg in the ESP group and 30.6 ± 6.23 mg in the C group (p < 0.001). Results showed that there was a significant difference between both groups in favour of the ESP group regarding visual analogue score (VAS) at rest and with coughing (p < 0.001). Conclusion: Our study findings show that US-guided ESP block exhibits a significant analgesic effect in patients undergoing thoracotomy surgery. Trial registration: ClinicalTrials.gov, NCT03749395. Registered 13 November 2018 [ABSTRACT FROM AUTHOR]

A novel modification for Green and Naghdi thermoelasticity model of type III is proposed in this article. This model is joined to other ones to treat a thermoelastic wave propagation problem in an annular disk. The closed-form solution of thermoelastic analysis of the annular disks has been presented to deduce temperature, radial displacement, dilatation and stresses. Results are illustrated and reported to compare the simple Green–Naghdi II and III and their modified single-, dual- and three-phase-lag models. Concluding remarks are added. [ABSTRACT FROM AUTHOR]

In this paper, the effects of hygrothermal conditions on various behaviors, such as bending, free vibration, mechanical and thermal buckling, of exponentially graded microplates lying on two-parameter elastic foundations are investigated. The trigonometric four-variable plate theory incorporated to the modified couple stress theory (MCST) is employed to derive the equations of motion. The present MCST contains an internal material length scale parameter, thus it can capture the size effect. The microplate is assumed to be subjected to a temperature rise and moisture concentration which are varied linearly through the thickness of the plate. Based on an exponential law, the material properties of the microplate are graded only in z direction. The equations of motion are solved analytically to obtain the displacements, stresses, eigenfrequencies and critical buckling load and temperature of the microplates. The present results are validated by comparing them with those previously published. The numerical examples reveal that considering the size effect and/or the elastic foundations leads to an increment in plate stiffness and thereby leads to a decrement in the deflection and an increment in eigenfrequency and buckling loads. It is also shown that the size effect is negligible for the thicker plate. [ABSTRACT FROM AUTHOR]

The modified couple stress theory (MCST) is utilized to investigate the bending of viscoelastic nanobeams laying on visco-Pasternak elastic foundations based on a new shear and normal deformations beam theory. This model consists of the material length scale coefficient that captures the size impact on small-scale beams. The simply supported beam is made of viscoelastic material, subjected to time harmonic transverse load. The nanobeam is presumed to be laying on double layers of foundations. The first layer is modeled as Kelvin–Voigt viscoelastic model and the second is taken as a shear layer. Based on the proposed beam theory and MCST, the differential motion equations are deduced using Hamilton's principle. To check the validity of the obtained formulations, the predicted results are compared with those available in the open literature. In addition, the influences of various parameters such as the material length scale parameter, length-to-depth ratio, viscoelastic damping structure, the stiffness and damping coefficients of the viscoelastic substrate, and shear and normal strains on the deflection and stresses are illustrated. [ABSTRACT FROM AUTHOR]

The present work is concerned with the bending analysis of viscoelastic sandwich microplates with carbon nanotubes (CNTs)-reinforced face sheets under the effects of a 2D magnetic field as well as hygrothermal conditions. The core layer is assumed to be a fully homogeneous viscoelastic material, whereas the face sheets are made of a polymer matrix stiffened by uniformly distributed or functionally graded (FG) CNTs. The applied magnetic field results in a body force (Lorentz force) that is applied to each particle of the plate. In order to take into account the size effect, the modified couple stress theory is employed containing only one length scale parameter. The viscoelastic sandwich microplate is assumed to be resting on two layers of the foundations. The first is modeled as the viscoelastic Kelvin–Voigt model. However, the second represents the elastic Pasternak shear layer. Based on the sinusoidal four-variable plate theory, four governing equations are obtained involving Lorentz force and foundation interaction. An analytical solution for the obtained equations is presented to get the displacements and stresses of the reinforced sandwich plates. The present solution is examined by introducing comparison examples. Influences of the geometric parameters, material length scale parameter, magnetic field parameter, damping parameters, temperature rise, moisture concentration, and foundation coefficients on the bending of the FG-CNTs-reinforced viscoelastic sandwich microplates are discussed. [ABSTRACT FROM AUTHOR]

AbstractThe purpose of this study is to analyze the influence of geometric parameters and material properties on the free and forced vibration of bi-directional functionally graded sandwich (2D-FGSW) plates lying on an elastic foundation (EF) using an effective finite element method (FEM) based on the trigonometric shear deformation theory (TrSDT). The mechanical properties of 2D-FGSW are variable in both the x- and z-directions. The EF includes the springer stiffness k1 and the shear layer stiffness k2. Moreover, the impacts of structural damping and periodic loading on the behavior of 2D-FGSW plates are considered. Element matrices are created using a four-node quadrilateral plate element (Q4) with eight degrees of freedom per node. The effectiveness and accuracy of the current formulation are confirmed by contrasting the acquired results with those of earlier works. Then, many studies are carried out to illustrate how input parameters might affect the vibration characteristics of 2D-FGSW plates lying on EF. In addition, the eigenfrequencies of different types of 2D-FGSW plates with a center hole are investigated. [ABSTRACT FROM AUTHOR]

Based on the differential quadrature procedure (DQP), the vibrational response of functionally graded (FG) sandwich annular plates enhanced with graphene platelets (GPLs) and with an FG porous core is illustrated in this paper. The current annular plate is assumed to deform axisymmetrically and expose to a radial magnetic field. The Lorentz magnetic body force is deduced via Maxwell's relations. The effective physical properties of the upper and lower layers of the sandwich plate are obtained by employing the Halpin–Tsai model. Our technique depends on a new four-unknown shear deformation theory to depict the displacements. In addition, the motion equations are established via Hamilton's principle. The motion equations are solved by employing the DQP. In order to study the convergence of the DQ method, the minimum number of grid points needed for a converged solution is ascertained. In addition, the current theory's outcomes are compared with those of previous higher-order theories. The effects of the porosity distribution type, porosity factor, GPLs distribution pattern, GPLs weight fraction, inner-to-outer radius ratio, outer radius-to-thickness ratio, magnetic field parameters, core thickness, and elastic substrate parameters on the nondimensional vibration frequencies are discussed. [ABSTRACT FROM AUTHOR]

This study is devoted to illustrate the mechanical buckling and free vibration analyses of double-porous functionally graded (FG) nanoplates embedded in an elastic foundation. A new quasi-3D refined plate theory is presented to model the displacement field. This theory contains only five unknown functions and considers the shear strain as well as thickness stretching. Based on the modified Mooney-type exponential relation, a new exponential law is presented to govern the materials variation and porosities distribution through the thickness of the nanoplates. The two porous nanoplates are bonded together by a set of parallel elastic springs and surrounded by Pasternak medium. The nonlocal strain gradient theory containing the nonlocal parameter and gradient coefficient is utilized to study the size-dependent effects. Based on Hamilton's principle, the equations of motion are drawn including the material parameters, elastic foundation reaction and biaxial compressive forces. An analytical approach for simply-supported and clamped bilayer porous FG nanoplates is implemented. The obtained results are compared with those available in the literature. Additional numerical calculations are introduced to show the influences of the material length scale parameters, inhomogeneity parameter, porosity factor and other parameters on the critical buckling and frequencies of the double-porous FG nanoplates. [ABSTRACT FROM AUTHOR]

Highlights • Bending of FGCNTs reinforced plate on elastic foundations is studied using Levy and Navier solutions. • The distribution of the CNTs is varied according to a modified power law. • The FGCNTs plate is subjected to uniform, linear, sinusoidal or exponential distributed loadings. • The homogeneous solution of the governing equations is obtained by the matrix method. • The method of undetermined coefficients is applied to find the particular solution. Abstract A new analytical approach for bending response of functionally graded single-walled carbon nanotube (FGCNT) reinforced plate resting on double-layered elastic foundations in thermal environments is presented based on Levy and Navier types solutions. The distribution of the carbon nanotubes is varied through the plate thickness in accordance with a modified power law. Four types of carbon nanotube distributions are considered. The four edges of the plate are simply supported for Navier method, whereas for Levy method, two opposite only of them are simply supported and the other ones are arbitrary. The present FGCNT plate is subjected to uniform, linear, sinusoidal or exponential distributed loadings. A refined shear deformation plate theory with four unknown functions is employed to obtain the closed form solution. The four coupled governing partial differential equations are derived utilizing Hamilton's principle. Applying Levy solution and then the state space concept to the governing equations, a nonhomogeneous first-order linear ordinary differential system with constant coefficients is obtained. The solution of the homogeneous system (homogeneous solution) is obtained by using the matrix method. While, the method of undetermined coefficients is applied to find the particular solution of the nonhomogeneous linear system. The results obtained by Navier and Levy methods are compared with available results in the literature. Several examples are discussed for various values of the foundation stiffness, CNT volume fraction, various types of plate geometries, CNT distributions, external applied loads and boundary conditions. [ABSTRACT FROM AUTHOR]

This research represents the first theoretical investigation about the vibration behavior of circular organic solar cells. Therefore, the vibration response of asymmetric circular organic solar cells that represent a perfect renewable energy source is demonstrated. For this purpose, the differential quadrature method (DQM) is employed. The organic solar cell is modeled as a laminated plate consisting of five layers of Al, P3HT:PCBM, PEDOT:PSS, ITO, and Glass. This cell is rested on a Winkler–Pasternak elastic foundation and assumed to be exposed to various types of hygrothermal loadings. There are three different kinds of temperature and moisture variations that are taken into account: uniform, linear, and nonlinear distribution throughout the cell's thickness. The displacement field is presented based on a new inverse hyperbolic shear deformation theory considering only two unknowns. The motion equations including hygrothermal effect and plate–foundation interaction are established within the framework of Hamilton's principle. The DQM is utilized to solve these equations. In order to ensure the accuracy of the proposed theory, the present results are compared with those reported by other higher-order theories. A comprehensive parametric illustration is conducted on the impacts of different parameters involving the geometrical configuration, elastic foundation parameters, temperature, and moisture concentration on the deduced eigenfrequency of the circular organic solar cells. [ABSTRACT FROM AUTHOR]

Abstract In this paper, an analytical treatment is developed for the magneto-electro-thermal bending of composite doubly-curved shallow shells reinforced by functionally graded graphene platelets (FGGPLs) surrounded by two piezoelectromagnetic (PEM) face sheets with various boundary conditions. According to new piece-wise mixture rules, four kinds of FGGPLs reinforced doubly-curved shells are considered. These shells are assumed to be exposed to thermal load, external electric voltage and magnetic potential. The material properties of FGGPLs multi-layered doubly-curved shallow shells are assumed to be varied in the shell thickness direction according to the suggested piece-wise distribution. Each layer of the composite shell is composed of polymer matrix reinforced with uniformly distributed graphene platelets. A four-variable shell theory is considered to describe the displacement field. In accordance with this theory, four equilibrium equations are derived from the virtual work principle. The governing equations are analytically solved to obtain the displacements, electric displacements, magnetic induction and stresses in the composite shells. A parametric study is presented to investigate the effects of the shell curvatures, boundary conditions, electric potential, magnetic potential, temperature rise and graphene platelets distribution type on the deflection, electric displacements, magnetic induction and stresses in FGGPLs reinforced laminated doubly-curved shells. It is found that the increment in the GPLs weight fraction and decrement in temperature increase the strength of the present structure. [ABSTRACT FROM AUTHOR]

Based on a new four-unknown shear deformation theory, the hygrothermal bending response of functionally graded (FG) sandwich plates lying on visco-Pasternak foundation is investigated in this work. The present sandwich plate is composed of a homogeneous ceramic core covered by two FG layers. The properties of face layers are graded according to a power law distribution in terms of volume fraction. The governing equations are derived from Hamilton principle containing the hygrothermal effects employing the suggested theory. This theory includes only four unknown functions and accounts for quasi-parabolic distribution of transverse shear stress. In addition, it satisfies the free traction conditions at the top and bottom surfaces of the plate. By varying the thickness of the core, several types of FGM sandwich plates are obtained and studied. By comparing the present results with those available in the literature, the present theory is validated. Parametric studies are executed to demonstrate the effects of humidity, temperature rise, foundation coefficients, core thickness, and power law index on the bending of FGM sandwich plates. [ABSTRACT FROM AUTHOR]

This work presents a nonlocal strain gradient theory for the dynamic deformation response of a single-layered graphene sheet (SLGS) on a viscoelastic foundation and subjected to a time harmonic thermal load for various boundary conditions. Material of graphene sheets is presumed to be orthotropic and viscoelastic. The viscoelastic foundation is modeled as Kelvin-Voigt's pattern. Based on the two-unknown plate theory, the motion equations are obtained from the dynamic version of the virtual work principle. The nonlocal strain gradient theory is established from Eringen nonlocal and strain gradient theories, therefore, it contains two material scale parameters, which are nonlocal parameter and gradient coefficient. These scale parameters have two different effects on the graphene sheets. The obtained deflection is compared with that predicted in the literature. Additional numerical examples are introduced to illustrate the influences of the two length scale coefficients and other parameters on the dynamic deformation of the viscoelastic graphene sheets. [ABSTRACT FROM AUTHOR]

In this paper, the size-dependent bending response of functionally graded piezoelectric (FGP) microplates resting on two-parameter elastic foundations and subjected to an external mechanical load, electric voltage and elevated temperature is investigated. The thermo-electro-mechanical loads are presumed uniformly distributed on the upper surface of the plate. To capture the size effect, the modified couple stress theory is employed. In this theory, the couple stress tensor is symmetric and it contains only one material length scale parameter. Based on a four-variable shear deformation plate theory, the governing equations are derived from Hamilton principle, which does not involve only the strain tensor but also the curvature tensor and electric field. The electrical and elastic properties of the microplate are assumed to be graded through the thickness of the plate according to a power law distribution as a function of the volume fraction of the constituents. The effects of the geometrical parameters (material length scale parameter, side-to-thickness ratio and plate aspect ratio), gradient index, electric voltage, elastic foundation stiffness and temperature parameters on the deflection, electric potential, stresses and electric displacements of the FGP microplates are all presented and discussed. [ABSTRACT FROM AUTHOR]

This article presents vibration characteristics of a piezoelectric viscoelastic nanoplate under various boundary conditions embedded in a visco-Pasternak's medium using nonlocal plate theory. The piezo-hygrothermal effects are all included. The hygrothermal piezoelectric nanoplate is made of orthotropic viscoelastic material. Also, the visco-Pasternak's medium is modeled according to a Kelvin-Voigt foundation. A Two-variable sinusoidal shear deformation plate theory is presented. The imaginary and real parts of the eigenfrequency of piezoelectric viscoelastic nanoplates which are associated with viscoelastic foundation, nonlocal parameter, as well as the viscoelastic structural damping coefficient, are obtained. The effects of other parameters such as aspect ratio, side-to-thickness ratio, temperature change, and moisture concentration are all investigated. The predicted results are compared with the corresponding ones in the literature to check their validation. Additional results are presented and suitable discussions are made. [ABSTRACT FROM AUTHOR]

The present work strives to explore some qualitative analysis for the governing equation describing the dynamic response of a piezoelectro-magnetic circular rod. As a result of the integrability study of the governed equation, which furnishes valuable insights into its structure, solutions, and applications in various fields, we apply the well-known Ablowitz–Ramani–Segur (ARS) algorithm to prove the non-integrability of the governed equation in a Painlevé sense. The qualitative theory for planar integrable systems is applied to study the bifurcation of the solutions based on the values of rod material properties. Some new solutions for the governing equation are presented and they are categorized into solitary and double periodic functions. We display a 3D representation of the solutions in addition to investigating the influence of wave velocity on the obtained solution for the particular material of the rod. [ABSTRACT FROM AUTHOR]

A new accurate four-variable shear deformation plate theory is introduced in this paper to illustrate the hygrothermal vibration and buckling of FGM sandwich plates resting on Winkler–Pasternak elastic foundations. Based on the suggested theory, the equations of motion are derived from Hamilton׳s principle containing the hygrothermal effects. This theory involves only four unknown functions and accounts for quasi-parabolic distribution of transverse shear stress. In addition, the transverse shear stresses are vanished at the top and bottom surfaces of the sandwich plate. A power law distribution is used to govern the gradation of material properties through the plate thickness. Various types of FGM sandwich plates are considered. To check the validity of the theory and formulations, the obtained results are compared with the previous results. Comparison studies reveal that the results of the proposed theory are more accurate than those of other shear deformation plate theories. Parametric study is performed to show the influences of moisture condition, temperature rise, elastic foundation coefficients and power law index on the buckling and natural frequency of FGM sandwich plates. [ABSTRACT FROM AUTHOR]

Vibration of orthotropic double-layered graphene sheets under hygrothermal conditions is investigated in this paper using the trigonometric shear deformation plate theory. This theory accounts for sinusoidal distribution of transverse shear stress, and satisfies the free transverse shear stress conditions on the top and bottom surfaces of the plate without using shear correction factor. Unlike the conventional shear deformation theory, the present trigonometric theory contains only two unknowns. The two layers are assumed to be bonded by an internal elastic medium and surrounded by external elastic foundations. The equations of motion are derived based on the nonlocal theory. The motion equations contain the small scale effect as will as hygrothermal effect. The present solution is examined by comparing the present results with those being in the open literature. The effects played by small scale parameter, temperature rise, the degree of moisture concentration, plate aspect ratio and side-to-thickness ratio are studied. [ABSTRACT FROM AUTHOR]

This work is devoted to investigate the bending response, free vibration, mechanical buckling and thermal buckling of functionally graded material (FGM) nanoplates embedded in an elastic medium. According to a new mixture law, the material properties of the FGM nanoplate are graded only in the thickness direction. The elastic medium is modeled as Pasternak’s two-parameter elastic foundations. The four-unknown shear deformation theory incorporated in Eringen’s nonlocal elasticity theory is employed to deduce the equations of motion from the Hamilton’s principle. The solutions of simply supported FGM nanoplates are obtained and the results are compared with those available in the literature. Detailed numerical studies are performed to demonstrate the influences of inhomogeneity parameter, nonlocal parameter, elastic foundation stiffness, plate aspect ratio and side-to-thickness ratio on the behavior of FGM nanoplates. [ABSTRACT FROM AUTHOR]

This paper deals with the investigation of the effect of hygrothermal conditions on the bending of nanoplates using Levy type solution model employing the state-space concept. The nanoplates are assumed to be subjected to a hygrothermal environment. The two-unknown function plate theory is used to derive the governing differential equations on the basis of Eringen's nonlocal elasticity theory. The governing equations contain the small scale effect as well as hygrothermal and mechanical effects. These equations are converted into a set of first-order linear ordinary differential equations with constant coefficients. Analytical solution of bending response for nanoplates under combinations of simply supported, clamped and free boundary conditions is obtained. Comparison of the results with those being in the open literature is made. The influences played by small scale parameter, temperature rise, the degree of moisture concentration, boundary conditions, plate aspect ratio and side-to-thickness ratio are studied. [ABSTRACT FROM AUTHOR]

This article presents a simplified three-unknown shear and normal deformations nonlocal beam theory for the bending analysis of nanobeams in thermal environment. Eringen's nonlocal constitutive equations are considered in the analysis. Governing equations are derived according to the present refined theory using Hamilton's principle. Central deflections of nanobeams under uniform and point loads are given and compared with the available ones in the literature. Additional results of displacement and stresses are presented for future comparison. The effects of nonlocality, temperature parameters, length of beam, length-to-depth ratio as well as shear and normal strains are all investigated. [ABSTRACT FROM AUTHOR]

Levy-type solution model is employed to demonstrate the bending response of single-layered graphene sheets subjected to a temperature field as well as external mechanical load. On the basis of Eringen׳s nonlocal elasticity equations incorporated with the two-variable plate theory, the governing differential equations of the thermomechanical response are derived by using the principle of virtual displacement. These equations are converted into a set of first-order linear ordinary differential equations with constant coefficients. The general solution of these equations can be obtained by using the state-space concept. Combinations of simply supported, clamped and free boundary conditions are considered. Comparison of the results with those being in the open literature is made. Numerical results are presented for rectangular sheets with different edge conditions, plate aspect ratios and nonlocal coefficient. [ABSTRACT FROM AUTHOR]

In the present study, the free vibration, mechanical buckling and thermal buckling analyses of multi-layered graphene sheets (MLGSs) are investigated. Eringen's nonlocal elasticity equations are incorporated in new two-variable plate theories accounting for small-scale effects. The MLGSs are taken to be perfectly bonded to the surrounding medium. The governing differential equations of this model are solved analytically under various boundary conditions and taking into account the effect of van der Waals forces between adjacent layers. New functions for the displacements are proposed here to satisfy the different boundary conditions. Comparison of the results with those being in the open literature is made. This comparison illustrates that the present scheme yields very accurate results. Furthermore, the influences of nonlocal coefficient, moduli of the surrounding elastic medium and aspect ratio on the frequencies and buckling of the embedded MLGSs are examined. [ABSTRACT FROM AUTHOR]

Abstract: In the present paper, the sinusoidal shear deformation plate theory (SDPT) is reformulated using the nonlocal differential constitutive relations of Eringen to analyze the bending and vibration of the nanoplates, such as single-layered graphene sheets, resting on two-parameter elastic foundations. The present SDPT is compared with other plate theories. The nanoplates are assumed to be subjected to mechanical and thermal loads. The equations of motion of the nonlocal model are derived including the plate foundation interaction and thermal effects. The governing equations are solved analytically for various boundary conditions. Nonlocal theory is employed to bring out the effect of the nonlocal parameter on the bending and natural frequencies of the nanoplates. The influences of nonlocal parameter, side-to-thickness ratio and elastic foundation moduli on the displacements and vibration frequencies are investigated. [Copyright &y& Elsevier]

Abstract: In the present work, thermal buckling of single-layered graphene sheets lying on an elastic medium is analyzed. For this purpose, the sinusoidal shear deformation plate theory in tandem with the nonlocal continuum theory, which takes the small scale effects into account, is employed. The non-linear stability equations, which contain the reaction of Winkler–Pasternak elastic substrate medium, are derived and then solved analytically for a plate with various boundary conditions and based on various plate theories. Closed form solutions are formulated for three types of thermal loadings as uniform, linear and nonlinear temperature rise through the thickness of the plate. A number of examples are presented to illustrate the numerical results concerned with the buckling temperature response of nanoplates resting on two-parameter elastic foundations. The influences played by transversal shear deformation, plate aspect ratio, side-to-thickness ratio, nonlocal parameter, and elastic foundation parameters are all investigated. [Copyright &y& Elsevier]

Abstract: In this paper, the analyses of dynamic deflection and stresses in functionally graded (FG) plates resting on two-parameter elastic foundations, according to Pasternakʼs model, are investigated. The present FG plate is subjected to time harmonic thermal load. Material properties of the plate are assumed to be graded in the thickness direction, from the upper surface which is ceramic-rich to the lower one which is metal-rich, according to a simple exponential law distribution in terms of the volume fractions of the constituents. The governing equations of the dynamic response of a non-homogeneous composite plate are deduced by using various shear deformation theories as well as the classical one. The influences of the time parameter, power-law index, side-to-thickness ratio and the foundation parameters on the dynamic bending are illustrated. [Copyright &y& Elsevier]

Abstract: This paper deals with the vibration and buckling behavior of exponentially graded material (EGM) sandwich plate resting on elastic foundations under various boundary conditions. New functions for midplane displacements are suggested to satisfy the different boundary conditions. The elastic foundation is modeled as Pasternak’s type which can be either isotropic or orthotropic and as a special case it converges to Winkler’s foundation if the shear layer is neglected. The present EGM sandwich plate is assumed to be made of a fully ceramic core layer sandwiched by metal/ceramic EGM coat. The governing equations of the dynamic response of non-homogeneous composite plates are deduced by using various shear deformation plate theories. Numerical results for the natural frequencies and critical buckling loads of several types of symmetric EGM sandwich plates are presented. The validity of the present solution is demonstrated by comparison with solutions available in the literature. The influences of the inhomogeneity parameter, aspect ratio, thickness ratio and the foundation parameters on the natural frequencies and critical buckling loads are investigated. [Copyright &y& Elsevier]

This work reports the investigations of the electric potential impacts on the mechanical buckling of the piezoelectric nanocomposite doubly curved shallow shells reinforced by functionally gradient graphene platelets (FGGPLs). A four-variable shear deformation shell theory is utilized to describe the components of displacement. The present nanocomposite shells are presumed to be rested on an elastic foundation and subject to electric potential and in-plane compressive loads. These shells are composed of several bonded layers. Each layer is composed of piezoelectric materials strengthened by uniformly distributed GPLs. The Halpin–Tsai model is employed to calculate the Young's modulus of each layer, whereas Poisson's ratio, mass density, and piezoelectric coefficients are evaluated based on the mixture rule. The graphene components are graded from one layer to another according to four different piecewise laws. The stability differential equations are deduced based on the principle of virtual work. To test the validity of this work, the current mechanical buckling load is analogized with that available in the literature. Several parametric investigations have been performed to demonstrate the effects of the shell geometry elastic foundation stiffness, GPL volume fraction, and external electric voltage on the mechanical buckling load of the GPLs/piezoelectric nanocomposite doubly curved shallow shells. It is found that the buckling load of GPLs/piezoelectric nanocomposite doubly curved shallow shells without elastic foundations is reduced by increasing the external electric voltage. Moreover, by increasing the elastic foundation stiffness, the shell strength is enhanced, leading to an increase in the critical buckling load. [ABSTRACT FROM AUTHOR]

Three-dimensional (3-D) asymmetric and axisymmetric bending analyses of solid circular and annular plates lying on an elastic medium with different boundary conditions are presented in this article. The present nanocomposite circular and annular plates are made of aluminum (Al) matrix reinforced with graphene platelets (GPLs) that uniformly distributed or functionally graded (FG) through the thickness. This model is exposed to transverse external load, thermal load and humid conditions as well as in-plane magnetic field. Lorentz magnetic force is obtained by applying Maxwell's equations. While, the temperature and moisture, along the transverse direction, are deduced by solving the one-dimensional heat conduction and moisture diffusion equations, respectively. The governing equations are established based on the three-dimensional elasticity theory. By applying the differential quadrature method (DQM) along both radial and thickness directions, the solution of magneto-hygrothermal bending of the circular and annular plates is obtained. Convergence and comparison investigations are introduced to illustrate the precision and validity of the present solution. The present paper aims to deduce the displacements and stresses of the FG graphene/metal circular and annular plates employing the DQM. Moreover, various parametric studies are presented to investigate the effects of outer-to-inner radius ratio, thickness to radius ratio, weight fraction of GPLs, boundary conditions, elastic foundation parameters, temperature, moisture concentrations on the stresses and displacements of the present model. • Magneto-hygrothermal bending of FG GPLs-reinforced circular plates is studied. • 3D numerical solution for bending of circular/annular plates is presented. • The DQM is applied along both the radial and transverse directions. • The results are presented for asymmetric and axisymmetric circular/annular plates. [ABSTRACT FROM AUTHOR]

This research is devoted to investigating the thermo-piezoelectric bending of functionally graded (FG) porous piezoelectric plates reinforced with graphene platelets (GPLs). A refined four-variable shear deformation plate theory is utilized considering the transverse shear strain to describe the displacement components. The porous nanocomposite plate is composed of polymer piezoelectric material containing internal pores and reinforced with FG GPLs. In accordance with modified distribution laws, the porosity and GPLs volume fraction are presumed to vary continuously through the plate thickness. Four GPLs and porosity distribution types are presented. By applying the Halpin–Tsai model, the elastic properties of the nanocomposite plate are calculated. The governing equations are derived based on the present theory and the principle of virtual work. The deduced partial differential equations are converted to ordinary equations by employing Levy-type solution. These equations are numerically solved based on the differential quadrature method (DQM). In order to determine the minimum grid points sufficient to gain a converging solution, a convergence study is introduced. Moreover, the accuracy of the present formulations are examined by comparing the obtained results with those published in the literature. Additional parametric analyses are introduced to investigate the influences of the GPLs weight fraction, distribution types, side-to-thickness ratio, external electric voltage and temperature on the thermal bending of FG GPLs porous nanocomposite piezoelectric plates. [ABSTRACT FROM AUTHOR]

In this paper, the nonlocal strain gradient theory and a new quasi 3D plate theory are employed to investigate the wave propagation in functionally graded (FG) porous graphene platelets (GPLs)-reinforced nanoplates on elastic foundations subjected to in-plane mechanical load and magnetic field. The present theory takes into account the shear deformation as well as the thickness stretching effect. The internal porosities and the GPLs are uniformly or non-uniformly distributed into the matrix according to four different types. The properties of the nanocomposites plates are calculated by utilizing the modified Halpin-Tsai pattern. Lorentz magnetic force is derived from Maxwell's equations for the conducting material. The motion equations are derived employing Hamilton's principle according to a new shear and normal deformations plate theory. Detailed parametric investigations on the wave frequency and phase velocity of the porous GPLs-reinforced nanoplates are implemented considering the influences of porosity coefficient, GPLs weight fraction, magnetic parameter and foundation stiffnesses on the results. It can be found that an increment occurs in the wave frequency with increasing the GPLs weight fraction and magnetic field parameter. While, it decreases as the pore coefficient increases. [ABSTRACT FROM AUTHOR]

This paper aims to study the hygrothermal buckling of smart graphene/piezoelectric circular nanoplates lying on an elastic medium and subjected to an external electric field. The circular nanoplates are made of piezoelectric polymer reinforced with graphene platelets that are uniformly distributed through the thickness of the nanoplate. The material properties of the nanocomposite plate are determined based on the modified Halpin-Tsai model. To capture the nanoscale effects, the nonlocal strain gradient theory is applied. Moreover, the principle of virtual work is employed to establish the nonlinear stability equations in the framework of classical theory. The differential quadrature method is utilized to solve the governing equations. Among the important aims of the paper is to study the influences of various parameters such as graphene weight fraction, elastic foundation parameters, external applied electric field, humid conditions, and boundary conditions on the thermal buckling of the smart nanocomposite circular nanoplates. It is found that the increase in graphene components and elastic foundation stiffness enhances the strength of the plates; therefore, the buckling temperature will increase. [ABSTRACT FROM AUTHOR]

Transient size-dependent mechanical and thermal buckling analyses of sandwich microplates with viscoelastic core and single-walled carbon nanotubes (CNTs)-reinforced face sheets are introduced in this paper. The CNTs are uniformly distributed or functionally graded (FG) through the thickness of the face layers. The viscoelastic sandwich microplate is resting on three-parameter viscoelastic foundations that modeled according to the viscoelastic Kelvin-Voigt model with a shear layer. Effects of a 2D magnetic field as well as hygrothermal conditions on the present analyses are studied. The modified couple stress model containing one material length scale parameter is employed to capture the small scale effect. A body force (Lorentz force) is deduced from Maxwell's magnetic equations, that is applied to each particle of the structure. The higher-order shear deformation plate theory with four unknowns is utilized to describe the displacement field. The stability equations are obtained using the principle of virtual displacement. By applying Navier method, the stability equations are solved to obtain the mechanical and thermal buckling of viscoelastic sandwich microplates. Various numerical examples are presented including the effects of the length scale parameter, moisture concentration, magnetic field parameter and other parameters on the buckling of the viscoelastic FGCNTs-reinforced sandwich microplates. [ABSTRACT FROM AUTHOR]

Based on the nonlocal strain gradient theory, the effect of an axial magnetic field on the free vibration and mechanical buckling responses of an FG graphene-reinforced sandwich deep curved nanobeam with viscoelastic core embedded in a viscoelastic medium is elucidated in this paper. The curved beam is also assumed to be exposed to axial external compressions. The volume fraction of the constituents of the composite face layers are presumed to be functionally graded through the thickness according to a layer-wise law. The material properties are calculated in the framework of Halpin-Tsai micromechanical scheme. Lorentz magnetic force is deduced employing electro-dynamic Maxwell's relations for a conducting body. According to a refined shear and normal deformations curved beam theory, the motion equations are introduced in the polar coordinates. Analytical solutions are obtained for the natural frequencies and critical buckling load of the viscoelastic sandwich curved nanobeams. By comparing the present results with the available data in the literature, the developed formulations are validated. Furthermore, other several numerical examples are performed to show the effects of different parameters including viscoelastic core thickness, magnetic field, structural and foundation damping factor, opening angle and graphene concentration on the frequency and buckling load of the viscoelastic sandwich curved beams. [ABSTRACT FROM AUTHOR]

Summary: Background and Aim: Predicting culprit lesions in acute coronary syndrome (ACS) could be a challenge. The aim of this study was to assess the accuracy of regional wall motion abnormalities (RWMA) using various echocardiographic techniques and ECG changes in predicting the culprit coronary lesion in a group of patients with ACS. Methods: In 80 consecutive patients with ACS (age 55·7 ± 9·4 years, 77% male, 15% with CCS Angina III), an echocardiographic examination of left ventricle (LV) RWMA, tissue Doppler imaging (TDI) and speckle tracking myocardial strain and strain rate (SR) were performed before intervention. Results: Of the 80 patients, one‐vessel stenosis (>70%) was present in 53 (66%), two‐vessel disease in 12 (15%) and multivessel disease in 15 patients (19%). About 51% of patients had hypertension, 40% diabetes and 23% dyslipidaemia. There was no relationship between individual segmental RWMA and SR. Mean regional SR, but not peak strain, correlated with culprit lesion branch: left anterior descending – LAD (r = 0·35, P = 0·005), circumflex LCx (r = 0·32, P = 0·03) and right coronary RCA (r = 0·37, P = 0·01). Only ECG changes in the LAD territory (r = 0·26, P = 0·04) correlated with the culprit lesion. SR of LAD territories ≤−0·74 was 71% sensitive and 70% specific (AUC = 0·70, CI = 0·67–0·93, P = 0·01), SR of LCx territories of ≤−0·67 was 75% sensitive and 63% specific (AUC = 0·72, CI = 0·58–0·87, P = 0·02) and SR of RCA territories ≤−0·83 was 73% sensitive and 71% specific (AUC = 0·80, CI = 0·66–0·93, P = 0·001) in predicting significant stenosis. SR was more accurate than all other techniques in predicting the culprit lesion. Conclusion: In ACS, mean regional speckle tracking SR is more sensitive than peak strain, TDI, ECG changes and wall motion abnormalities in detecting significant coronary artery stenosis. [ABSTRACT FROM AUTHOR]

This paper presents a novel hybrid design technique to minimize the number of layers of the transmitarray (TA) panel while maintaining 360° phase shift range. Two types of unit cells, the receive–transmit unit cell and the frequency selective surface (FSS), are placed in the same aperture. The resulting TA panel is very thin but does not sacrifice the radiation efficiency of the array. The receive–transmit unit cell is an aperture-coupled square patch, and the FSS unit cell is a novel wide bandpass FSS. Both types of unit cells have three conductive layers and are printed on two substrates with a total thickness of 0.07λ0. The developed hybrid TA shows better gain than a homogeneous TA using the same elements. Meanwhile, it has comparable radiation performance but with a much lower profile compared to the conventional FSS-based TA designs that use several substrates separated by air layers. To verify the design concept, two hybrid TAs of different sizes with central frequency at 13.3 GHz were designed and fabricated. The measurements show that the TAs have at least 6.7% 1 dB gain bandwidth and higher than 30% aperture efficiency. Compared to the existing ultrathin designs of similar panel thickness, the presented TAs do not suffer from the phase quantization loss and achieve better or similar bandwidths. [ABSTRACT FROM AUTHOR]

This paper presents a novel sequentially rotated patch array antenna with dual circular polarizations (CP). The present design has the advantages of compact size, simple feed networks, low cross polarization, and high isolation. The radiating elements are dual linearly polarized (LP) equilateral triangular patches with hybrid feeds. The vertical polarization (VP) of the patch antenna is obtained by using an aperture-coupled feed and the horizontal polarization (HP) is obtained by using a proximity feed. These two feeds are orthogonally positioned and are printed on different PCB layers, which leads to the high isolation between these two ports and facilitates the design of the feed networks. The array antenna consists of six such dual-LP triangular patches sequentially rotated by 60 ^\circ and fed by separated feed networks. Since LP antenna elements are used, the design of the feed network is much simplified. Through sequentially varying the feeding phase by \pm 60^\circ, dual circular polarizations are obtained. The operation principle of the array antenna is also analytically explained in this paper. To verify the design concept, one dual LP equilateral triangular patch and one dual CP equilateral triangular patch array resonating at 10.5 GHz are designed, fabricated, and tested. There is a good agreement between the simulation and measurement results, both of which show that the array antenna exhibits high port isolation and good circular polarizations with low cross polarization at different planes. The proposed design technique can be applied to the design of dual CP array antennas operating at other frequency bands. [ABSTRACT FROM PUBLISHER]

Abstract: In this article, the small scale effect on the bending of nanoplates, such as graphene sheets, embedded in two-parameter elastic medium and subjected to hygro-thermo-mechanical loading is studied. The temperature field and moisture concentrations are assumed to be varied uniformly, linearly or nonlinearly through the thickness of the nanoplates. Based on the nonlocal continuum theory in conjunction with the refined sinusoidal shear deformation plate theory, the governing equations are derived including the hygro-thermal effects and the reaction between the plate and the elastic medium. The nonlocal mechanics account for the small size effects when dealing with nanosize elements. However, the refined sinusoidal shear deformation plate theory takes account the normal as well as shear deformation effects. A parametric study is carried out varying the small scale parameter, temperature, moisture concentration, elastic foundation parameters, plate aspect ratio and side-to-thickness ratio of the nanoplate with simply supported condition. [Copyright &y& Elsevier]

A new investigation on hygrothermal stress analysis of rotating functionally graded (FG) graphene/metal sandwich cylindrical shell having an auxetic honeycomb core is presented in this article. It is assumed that the simply-supported sandwich shell is spinning about its axial axis with a constant angular speed. The sandwich faces are composed of concentric multi-shells with uniformly distributed GPLs through the thickness of each shell. The material properties of the face layers are varied based on a layer-wise law. The one-dimensional heat conduction and moisture diffusion equations are used to obtain the applied temperature and moisture, respectively. The first-order shear deformation theory are employed to describe the displacement field. The minimum potential energy principle, which contains the initial hoop tension and the centrifugal effect due to the spinning motion of the cylindrical shell, is used to establish the governing equations. The stresses and displacements of the composite cylindrical shells are obtained from the analytical solution of the governing equations. Parametric examples are presented with focusing attention on the effects of the GPLs weight fraction, spinning speed of the cylindrical shell, core-to-face thickness ratio, length-to-radius ratio, radius-to-thickness ratio, temperature and moisture on the bending response of spinning nanocomposite cylindrical shells with an auxetic core. • For the first time, hygrothermal deformation of a simply-supported spinning cylindrical shell is presented. • The present structure "FG graphene sandwich cylindrical shells with honeycomb core" is considered for the first time. • The sandwich shell is spinning about its axial axis with a constant angular speed. • The sandwich faces are composed of concentric multi-shells with uniformly distributed GPLs through the thickness. • The heat conduction and moisture diffusion equations are used to obtain the applied temperature and moisture. [ABSTRACT FROM AUTHOR]